Radical Reactor With Inverted Orientation

ABSTRACT

A radical reactor including an elongated structure received within a chamber of a body of the radical reactor. Radicals are generated within a radical chamber formed in the elongated structure by applying a voltage signal across the elongated structure and an electrode extending within the radical chamber. The radicals generated in the radical chamber are routed via a discharge port of the elongated structure and a conduit formed in the body of the radical reactor onto the substrate. The discharge port and the conduit are not aligned so that irradiation generated in the radical chamber is not directed to the substrate

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of co-pending U.S. patentapplication Ser. No. 14/398,898, filed on Nov. 4, 2014, which is a U.S.national phase application of International Patent Application No.PCT/US2013/038624 filed on Apr. 29, 2013, which claims priority to andthe benefit of U.S. Provisional Patent Application No. 61/643,159 filedon May 4, 2012, all of which are incorporated by reference in theirentirety.

BACKGROUND

1. Field of Art

The present disclosure relates to a radical reactor with a dischargeport and a conduit configured in a way to prevent irradiation generatedfrom a plasma chamber from reaching a substrate.

2. Description of the Related Art

Plasma is partially ionized gas consisting of large concentrations ofexcited atomic, molecular, ionic, and free-radical species. The radicalsgenerated by plasma can be used for various purposes, including (i)chemically or physically modifying the characteristics of a surface of asubstrate by exposing the surface to the reactive species or radicals,(ii) performing chemical vapor deposition (CVD) by causing reaction ofthe reactive species or radicals and source precursor in a vacuumchamber, and (iii) performing atomic layer deposition (ALD) by exposinga substrate adsorbed with source precursor molecules to the reactivespecies or radicals.

There are two types of plasma reactors: (i) a direct plasma reactor, and(ii) a remote plasma reactor. The direct plasma reactor generates plasmathat comes into contact directly with the substrate. The direct plasmareactor may generate energetic particles (e.g., free radicals, electronsand ions) and radiation that directly contact the substrate. Suchcontact may cause damage to the surface of the substrate and alsodisassociate source precursor molecules adsorbed in the substrate.Hence, the direct plasma reactor has limited use in fabrication ofsemiconductor devices or organic light emitting diode (OLED) devices.

A remote plasma device generates plasma at a location remote from thesubstrate. When generating the plasma, other undesirable irradiation ofelectrons, ultraviolet ray or ions may also result from the plasma. Thesubstrate may be exposed to such irradiation and cause damage to thesubstrate or make undesirable changes to the properties of thesubstrate.

SUMMARY

Embodiments related to a radical reactor for injecting radicals to asubstrate. The body of the radical reactor is formed with a cavityextending across the body and a conduit from the cavity to a surface ofthe body facing a substrate passing across the radical reactor. Theradical reactor includes an elongated structure contained in the cavity.The elongated structure formed with a radical chamber for receiving gasthrough a passage in the elongated structure and generating radicals bydisassociating the received gas. The radicals are discharged from theelongated structure into the cavity via a discharge port not alignedwith the conduit of the body to prevent irradiation generated in theradical chamber from reaching the substrate.

In one embodiment, an electrode extends across a length of the elongatedstructure. A voltage signal applied across the elongated structure andthe electrode to generate the radicals.

In one embodiment, the conduit is configured to discharge the radicalsonto the substrate from a first side of the radical reactor, and thedischarge port is formed in the elongated structure to open towards asecond side of the radical reactor opposite to the first side of theradical reactor.

In one embodiment, the first side is a bottom of the radial reactor andthe second side is a top of the radical reactor.

In one embodiment, paths from the discharge port to the conduit areprovided at both sides of the elongated structure.

In one embodiment, the passage includes a channel extending lengthwiseacross the elongated structure and perforations connecting the channeland the radial chamber.

In one embodiment, the elongated structure is separate from andremovable from the body.

In one embodiment, the elongated structure is integrated with the body.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross sectional diagram of a linear deposition device,according to one embodiment.

FIG. 2 is a perspective view of a linear deposition device, according toone embodiment.

FIG. 3 is a perspective view of a rotating deposition device, accordingto one embodiment.

FIG. 4A is a perspective view of a radical reactor in a depositiondevice, according to one embodiment.

FIG. 4B is a cross-sectional view of the radical reactor of FIG. 4A,according to one embodiment.

FIG. 5 is a flowchart illustrating a method of generating and injectingradicals onto the substrate, according to one embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments are described herein with reference to the accompanyingdrawings. Principles disclosed herein may, however, be embodied in manydifferent forms and should not be construed as being limited to theembodiments set forth herein. In the description, details of well-knownfeatures and techniques may be omitted to avoid unnecessarily obscuringthe features of the embodiments.

In the drawings, like reference numerals in the drawings denote likeelements. The shape, size and regions, and the like, of the drawing maybe exaggerated for clarity.

Embodiments relate to a radical reactor including an elongated structurereceived within a chamber formed in a body of the radical reactor.Radicals are generated within a radical chamber formed in the elongatedstructure by applying a voltage signal across the elongated structureand an electrode extending within the radical chamber. The radicalsgenerated in the radical chamber are routed via a discharge port of theelongated structure and a conduit formed in the body of the radicalreactor onto the substrate. The discharge port and the conduit are notaligned so that irradiation generated in the radical chamber is notdirected to the substrate.

As used herein, when “A” and “B” are “aligned,” it means that there isat least one straight path from “A” to “B”.

FIG. 1 is a cross sectional diagram of a linear deposition device 100,according to one embodiment. FIG. 2 is a perspective view of the lineardeposition device 100 (without chamber walls to facilitate explanation),according to one embodiment. The linear deposition device 100 mayinclude, among other components, a support pillar 118, the processchamber 110 and one or more reactors 136. The reactors 136 may includeone or more of injectors and radical reactors. Each of the injectorsinjects source precursors, reactant precursors, purge gases or acombination of these materials onto the substrate 120. As describedbelow in detail with reference to FIG. 5, source precursors and/orreactant precursors may be radicals of a gas mixture. Each of theradical reactors is a remote plasma reactor that generates radicals ofgas supplied to the radical reactor, as described below in detail withreference to FIGS. 4A and 4B.

The process chamber enclosed by the walls may be maintained in a vacuumstate to prevent contaminants from affecting the deposition process. Theprocess chamber 110 contains a susceptor 128 which receives a substrate120. The susceptor 128 is placed on a support plate 124 for a slidingmovement. The support plate 124 may include a temperature controller(e.g., a heater or a cooler) to control the temperature of the substrate120. The linear deposition device 100 may also include lift pins (notshown) that facilitate loading of the substrate 120 onto the susceptor128 or dismounting of the substrate 120 from the susceptor 128.

In one embodiment, the susceptor 128 is secured to brackets 210 thatmove across an extended bar 138 with screws formed thereon. The brackets210 have corresponding screws formed in their holes receiving theextended bar 138. The extended bar 138 is secured to a spindle of amotor 114, and hence, the extended bar 138 rotates as the spindle of themotor 114 rotates. The rotation of the extended bar 138 causes thebrackets 210 (and therefore the susceptor 128) to make a linear movementon the support plate 124. By controlling the speed and rotationdirection of the motor 114, the speed and the direction of the linearmovement of the susceptor 128 can be controlled. The use of a motor 114and the extended bar 138 is merely an example of a mechanism for movingthe susceptor 128. Various other ways of moving the susceptor 128 (e.g.,use of gears and pinion at the bottom, top or side of the susceptor128). Moreover, instead of moving the susceptor 128, the susceptor 128may remain stationary and the reactors 136 may be moved.

FIG. 3 is a perspective view of a rotating deposition device 300,according to one embodiment. Instead of using the linear depositiondevice 100 of FIG. 1, the rotating deposition device 300 may be used toperform the deposition process according to another embodiment. Therotating deposition device 300 may include, among other components,reactors 320A, 320B, 334A, 334B, 364A, 364B, 368A, 368B, a susceptor318, and a container 324 enclosing these components. A set of reactors(e.g., 320A and 320B) of the rotating deposition device 300 correspondto the reactors 136 of the linear deposition device 100, as describedabove with reference to FIG. 1. The susceptor 318 secures the substrates314 in place. The reactors 320A, 320B, 334A, 334B, 364A, 364B, 368A,368B are placed above the substrates 314 and the susceptor 318. Eitherthe susceptor 318 or the reactors 320, 334, 364, 368 rotate to subjectthe substrates 314 to different processes.

One or more of the reactors 320A, 320B, 334A, 334B, 364A, 364A, 368B,368B are connected to gas pipes (not shown) to provide source precursor,reactor precursor, purge gas and/or other materials. The materialsprovided by the gas pipes may be (i) injected onto the substrate 314directly by the reactors 320A, 320B, 334A, 334B, 364A, 364B, 368A, 368B,(ii) after mixing in a chamber inside the reactors 320A, 320B, 334A,334B, 364A, 364B, 368A, 368B, or (iii) after conversion into radicals byplasma generated within the reactors 320A, 320B, 334A, 334B, 364A, 364B,368A, 368B. After the materials are injected onto the substrate 314, theredundant materials may be exhausted through outlets 330, 338. Theinterior of the rotating deposition device 300 may also be maintained ina vacuum state.

FIG. 4A is a perspective view of a radical reactor 136A, according toone embodiment. A substrate 420 is secured to a susceptor 428 that movesrelative to the radical reactor 136A, as shown by arrow 451. The reactor136A may be a radical reactor that generates radicals of gas or a gasmixture received from one or more sources. The gas or gas mixtures areinjected into the reactor 136B via a pipe 414, and are converted intoradicals within the reactor 136A by applying voltage across electrodes.The radicals are injected onto the substrate 420, and remaining radicalsand/or gas reverted to an inactive state are discharged from the reactor136A via exhaust port 438.

FIG. 4B is a cross-sectional view of the radical reactor 136A takenalong line A-B of FIG. 4A, according to one embodiment. The radicalreactor 136A includes, among other components, a body 410, a middle bar464, an electrode 462 extending lengthwise in the middle bar 464. Thebody 410 is formed with cavity 476 to house the middle bar 464. Thecross-section of the cavity 476 is elliptic and the cavity 476 extendssubstantially across the length L of the radical reactor 136A. When themiddle bar 464 is installed in the middle of the cavity 476, the cavity476 provides two separate paths for radicals to travel to the substrate420, one at the left side and the other at the right side of the middlebar 464 as shown by two dashed lines in FIG. 4B.

The middle bar 464 is an elongated structure formed with a channel 450and perforations 454 (holes or slits) to convey the gas or gas mixturesreceived from the pipe 414 to a radical chamber 458. Radicals aregenerated in the radical chamber 458 by disassociating the conveyed gasor gas mixture. The disassociation may be performed by generating plasmain the radical chamber 458 or exposing the gas or gas mixtures tomicrowave.

In one embodiment, the radical chamber 458 is defined by the electrode462 and the inner surface 472 of the middle bar 464 that functions asanother electrode. A voltage signal is applied between the electrode 462and the middle bar 464 to generate plasma in the radical chamber 458.When the gas or gas mixtures are provided to the radical chamber 458while the voltage signal being applied to the electrodes, the plasma inthe radical chamber 458 generates radicals. Since the plasma isgenerated away from the substrate 420, the radical reactor 136A is atype of remote plasma reactor.

The radicals flow into the cavity 476, a conduit 480, a constrictionzone 482 and then into the exhaust port 438. The conduit 480 is formedin the body 410 of the radical reactor 136A and connects the cavity 476to an area directly above the substrate 420.

A discharge port 468 is formed at a side of the middle bar 464 andconfigured so that at least part of the path from the discharge port 468to the substrate 420 is not aligned. Hence, there is no straight pathfrom the discharge port 468 to the substrate 420. In the example of FIG.4B, a discharge port 468 is formed at the upper part of the middle bar464 to discharge radicals generated in the radical chamber 458 into thecavity 476. The conduit 480 is formed at a bottom part of the cavity476. Hence, the discharge port 468 is not aligned with the conduit 480.By having the discharge port 468 not aligned with the conduit 480,irradiation generated in the radical chamber 458 (e.g., ultravioletlight or electron beam) is blocked by the body 410 before reaching thesubstrate 420. Hence, the substrate 420 is not damaged or negativelyinfluenced by such irradiation.

The generated radicals come into contact with the substrate 420 belowthe conduit 480. As the radicals travel from the discharge port 468 tothe substrate 420 (as shown by dashed curve lines), some radicals mayrevert to gas in an inactive state. Such inactive gas is also dischargedvia the constriction zone 482 and the exhaust port 438.

The constriction zone 482 has height h that is lower than height H ofthe conduit 480. Hence, the gas while passing through the constrictionzone causes Venturi effect. Venturi effect enables removal of anyredundant material remaining on the substrate 420 after exposure to theradicals or from a previous process, and therefore, contributes toenhanced quality of layer formed on the substrate 420.

In other embodiments, the discharge port may be formed at a side of themiddle bar 464 other than the bottom of the middle bar 464. In this way,the plasma generated in the radical chamber 458 is not irradiated ontothe substrate 420, and hence, the substrate 420 is not damaged ornegatively influenced by irradiation from the plasma.

In one embodiment, the middle bar 464 and the electrode 462 aremodularized for removal and replacement. These components can be easilyremoved from the radical reactor 136A and replaced with new parts. Inthis way, the entire radical reactor 136A need not be replaced whenthese components are broken or not performing in a desired way.

In another embodiment, the middle bar 464 is integrated with and formspart of the body 410. In this embodiment, the middle bar 464 is notseparable from the body 410.

FIG. 5 is a flowchart illustrating a method of generating and injectingradicals onto the substrate, according to one embodiment. First, gas issupplied 510 into the radical chamber 458 of the middle bar 464 placedin the cavity 476 of the body 410 of the radical reactor 136A. Theradicals of the supplied gas is generated 520 in the radical chamber 458by applying a voltage signal across the middle bar 464 and an electrode462 extending across the radical chamber 458.

The generated radicals are discharged 530 into the cavity 476 via adischarge port 468 formed at one side of the middle bar 464. Theradicals are routed 540 to the conduit 480 via the cavity 476. Theconduit 480 is not aligned with the discharge port 468 to preventirradiation generated in the radical chamber 458 from reaching andaffecting the substrate 420. The radicals received in the conduit arerouted 550 onto the substrate 420.

Although the present invention has been described above with respect toseveral embodiments, various modifications can be made within the scopeof the present invention.

1. A method of discharging radicals onto a substrate, comprising:supplying gas into a radical chamber formed in an elongated structureplaced in a cavity of a body of a radical reactor; generating radicalsin the radical chamber by disassociating the supplied gas; dischargingthe radicals into the cavity via a discharge port formed at a side ofthe elongated structure; routing the discharged radicals to a conduitformed in the body and connected to the cavity, wherein the conduit isnot aligned with the discharge port to prevent irradiation generated inthe radical chamber from reaching the substrate; and routing theradicals onto the substrate via the conduit.
 2. The method of claim 1,wherein the supplied gas is disassociated by applying a voltage signalacross the elongated structure and an electrode extending within theradical chamber.
 3. The method of claim 1, wherein the radicals aredischarged from the radical chamber to the cavity towards a side of theradical reactor, and wherein the radicals are discharged from theconduit onto the substrate towards another side of the radical reactoropposite to the side of the radical reactor.
 4. The method of claim 1,wherein the discharged radicals are routed via paths provided at bothsides of the elongated structure.
 5. The method of claim 1, wherein theradicals are discharged into the cavity via the discharge port in afirst direction, and wherein a surface of the body faces the substratein a second direction different from the first direction.
 6. The methodof claim 5, wherein the second direction is opposite to the firstdirection.
 7. The method of claim 5, wherein the radicals are routedfrom the discharge port into the conduit along a curved path.
 8. Themethod of claim 5, wherein the radicals are routed onto the substrate inthe second direction.
 9. The method of claim 1, wherein the substratedoes not face the discharge port.
 10. The method of claim 1, wherein thedischarged radicals are routed to the conduit through a path between theelongated structure and the body.
 11. The method of claim 1, furthercomprising discharging remaining radicals away from the substrate via anexhaust.
 12. The method of claim 11, wherein the remaining radicals aredischarged away from the substrate via the exhaust in a first direction.13. The method of claim 12, wherein the radicals are discharged into thecavity via the discharge port in the first direction.
 14. The method ofclaim 13, wherein the radicals are routed onto the substrate in a seconddirection different from the first direction.
 15. The method of claim14, wherein the second direction is opposite to the first direction. 16.The method of claim 11, further comprising passing the radicals througha constriction zone between the exhaust and the conduit, wherein Venturieffect is caused in the constriction zone.